How to Corner Balance Your Car with Coilovers

This article was written by Coilovers.com Owner and Principal, Lou Tortola.

You just bolted in a coilover kit. The car sits right and looks right. Yet it turns in sharper one way than the other, and it squirms a little under hard braking. Before you blame the springs, put the car on scales. Corner balancing sets how the car's weight splits across its two diagonals, so the chassis behaves as evenly as it can turning left and right. Here is what it is, what it can and cannot fix, and how to do it.

What Is Corner Balancing?

Corner balancing means adjusting the height at each corner of your coilovers so the car's weight is shared evenly between the two diagonals. The number you chase is cross weight. Cross weight is the right front plus the left rear, divided by total weight. The target is 50%.

Think of a four-legged table on an uneven floor. One leg ends up carrying less, and the table rocks onto the opposite pair. A car does the same thing through its springs. It never lifts a wheel at rest, but one diagonal pair quietly carries more load than the other.

Here is the part most guides get wrong. Corner balancing cannot make all four tires carry the same load. Front to rear and left to right splits are set by where the mass sits: engine, fuel, battery and driver. Spring perches only move load between the diagonals. All four corners can only match if the car is already 50/50 both ways, and few cars are.

Weigh the car the way it will be driven. Put the driver in the seat, or add the same weight as ballast in the driver's seat.

Why Corner Balancing Matters

Understanding Weight Distribution

Your scales give you three splits: front to rear, left to right, and cross weight. Front to rear affects how much load sits on the driven tires and how the car balances under braking. Left to right shows how far the driver and components sit off center. You can only change those two by moving mass, such as relocating the battery or adding ballast.

Cross weight is the one your coilovers control. When it sits away from 50%, the car carries more load on one diagonal. In practice, it tends to push more in one direction and rotate more in the other. It can also pull under braking and wear tires unevenly. More spring rate or more damping will not fix that. Getting the diagonals even will.

A quick word on unsprung weight, because it comes up. Unsprung weight is the mass the springs do not carry: wheels, tires, hubs, brakes and part of the arms. It matters for how well the tire follows a bumpy road. It does not change what the scales read. Each pad reads the total load at that tire, sprung and unsprung together.

Benefits of Corner Balancing

Corner balancing is one of the most useful tuning steps on an adjustable coilover kit. Done right, the car turns in the same way both directions, brakes straighter and wears its tires more evenly. On the street it feels calmer and more settled at speed.

Be clear about what it does not do. It does not reduce body roll or pitch. Those come from spring rates, anti-roll bars, damping and suspension geometry. Corner balancing evens out the load on each diagonal. That is its whole job.

Any height-adjustable coilover kit lets you do this, including kits from BC Racing, KW and Fortune Auto. The adjustment is already built in. You just need scales and a method.

Preparation for Corner Balancing

Required Tools and Equipment

You need four things to corner balance:

• Four corner scales, one pad under each tire. Most systems read every corner at once and work out the cross weight for you.
• Ramps or leveling plates so all four pads sit on the same flat, level plane. A floor that slopes even a little skews the numbers.
• Wheel chocks to keep the car from rolling off the pads.
• A floor jack and the wrenches for your kit, so you can lift a corner and turn the adjusters.

Scale systems vary widely in capacity and features, from basic pads to wireless sets. Plenty of shops also do corner balancing as a service, so you do not have to own scales to get it done.

Setting Up the Car

Set ride height first, using our guide to set ride height on coilovers. Corner balancing moves each corner by small amounts, so start close to your target. On a full-length kit like BC Racing or Fortune Auto, ride height is set at the lower mount. The spring perch sets preload. On a perch-only sleeve kit, the perch sets both together.

Then set the car up the way it will run. Set tire pressures to your normal spec. Put the fuel at the level you usually drive or race with. Put the driver or ballast in the seat. Lock every locking collar you are not adjusting.

The Corner Balancing Process

How to Corner Balance a Car, Step by Step

1. Roll onto the scales. Make sure all four pads sit level with each other. Let the car settle. Record left front, right front, left rear, right rear, total weight and cross weight.
2. Read the cross weight. Above 50% means the right front and left rear diagonal is carrying extra load. Below 50% means the left front and right rear diagonal is. Either way, you correct it by changing corner heights.
3. Lift and adjust. Jack up the corner you want to change and turn its adjuster. Raising a corner adds load to that corner and to its diagonal partner. It takes load off the other two corners. Lowering a corner does the reverse. Make small moves, especially with stiff springs.
4. Settle and remeasure. Lower the car and roll it back and forth a little, or bounce each corner a few times. That frees any bind in the bushings. Take new readings only once the numbers stop moving.
5. Lock it in. Once cross weight sits at or near 50%, tighten every locking collar. Reconnect the anti-roll bar end links. Write down your final corner weights and ride heights.

Making Adjustments to Coilovers

Your coilover kit is the tool that makes corner balancing possible. Each corner adjusts on its own, so you can move load between the diagonals without touching the rest of the car.

A neat trick is to work in pairs. Raise one diagonal pair a little and lower the other pair by the same amount. That moves cross weight while keeping average ride height close to where it was.

Spring rate and the corner's motion ratio decide how sensitive the car is. With stiff springs, a small turn shifts a lot of load. With softer street springs, each turn does less, so you have more room to work. Small moves and patience get you there.

On a full-length kit, you can make the height change at the lower mount and leave the spring perch where you set preload. That is how BC Racing and Fortune Auto kits are built to adjust. If you later fit Swift Springs SPEC-R springs on a BC Racing kit, the free length changes. Re-check ride height and corner weights after the swap.

Damping has no effect on static corner weights. Turn the damping adjusters on a KW V3 or a BC Racing BR Series all you like. The scales will not move. Corner height moves the scales.

Reading the Scales Correctly

The display shows each corner weight, total weight, front to rear, left to right and cross weight. Your target is cross weight at or near 50%. Front to rear and left to right are information, not targets. Perches cannot change them.

Watch for numbers that keep drifting. That usually means something is binding. Check that all four pads are level. Check tire pressures again. Make sure nothing is resting on a bump stop or rubbing.

The method is the same on every brand of coilover, whether it is BC Racing, KW, Fortune Auto, TEIN or Öhlins. What changes from kit to kit is how the height adjusts and how stiff the springs are. Follow your kit's manual for where to turn and what to lock.

Final Adjustments and Alignment

Common Mistakes to Avoid

The most common mistake when corner balancing a car is reading weights before the suspension settles. Roll or bounce the car after every change. The second is making big moves. Go in small steps and remeasure each time.

Do not balance with a preloaded anti-roll bar. Do not weigh on a floor that is not level. And do not chase a 50% left to right split with the perches. It cannot be done that way, and you will wreck your cross weight trying.

One more. Confirm ride height is close to target before you start. Balancing around the wrong height means doing it twice.

Post-Balance Alignment

Get a full four-wheel alignment after you balance. Changing corner heights changes camber and toe. Our guide to suspension geometry and alignment covers the settings. Any change in ride height calls for an alignment, and corner balancing is a set of small height changes.

Some shops balance, align, then check the scales one last time. That is a sound habit. Corner balancing and alignment work together, and neither replaces the other in a well-sorted performance suspension setup.

Keep reading: Our guide to alignment after lowering. Once the car is balanced, take it somewhere. Here are race tracks by province.

Frequently Asked Questions